The fundamental goals of this research proposal are to test the hypotheses that: 1) application of thermal energy at 65 degrees C using radio-frequency energy to the coxofemoral joint capsule of puppies with radiographic evidence of joint laxity will result in normal hip congruity, 2) will prevent the development of the lameness and the cartilagenous and bony changes characteristic of CHD, and 3) will not have detrimental effects on the biomechanical or viscoelastic properties of the joint capsular tissue. These investigations will yield insights into the fundamental mechanisms of thermal modification of musculoskeletal soft tissue. This research program is designed to determine whether thermal modification of coxocofemoral joint capsule of 16-week-old puppies with excessive joint: laxity will prevent CHD. Ultimately, this model will serve to evaluate the potential of thermal energy to reduce excessively lax coxofemoral joints in neonatal children and thereby help prevent DDH. The candidate of this application graduated magna cum laude from Humboldt State University with a B.S. in cellular-molecular biology and a minor in chemistry. She worked as a molecular biologist at Amgen, Thousand Oaks, CA, before undertaking and; completing her D.V.M. at the University of California-Davis. Dr. Lopez was awarded 5 scholarships and 2 research grants while a D.V.M. student. She completed an internship at Kansas State University and a large animal surgery residency/Master's degree at they University of Wisconsin- Madison. She is a board certified large animal surgeon. Dr. Lopez's Master's thesis was entitled "Effects of Radio-frequency Energy on Ovine Stifle Joint Capsule", and she performed much of the early radio- frequency work in the Comparative Orthopaedic Research Laboratory. She was awarded an NRSA in 1998 and has performed the background research and preliminary, studies that form the basis for this proposal. She passed her preliminary examinations "With Honors" in November, 1999, and is scheduled to complete her PhD in June 2001. Her ultimate goal is to join the faculty of an academic institution as a well-trained scientist and productive researcher specializing in integrative, translational research. The training environment will be guided toward mentoring the candidate while teaching valuable research techniques necessary to begin an independent research career. The majority of supervision will be provided by Mark D. Markel, an internationally known and respected investigator in the area of thermal tissue modification, Professor of Surgery, and Professor and Chairman of Medical Sciences. The advisory committee will consist of well-respected and highly experienced individuals within the University. The Comparative Orthopaedic Research Laboratory is a well established laboratory that houses multi- disciplinary research programs. The University of Wisconsin provides an exceptional environment for interaction with experts in a variety of fields, and it is well known for its exceptional research programs, especially in the medical sciences.